1. Field Of The Invention
This invention relates to a vaporizer and more specifically it relates to a vaporizer for use with a high-frequency jet ventilator and an associated method.
2. Brief Description Of The Prior Art
High-Frequency Jet Ventilation (HFJV) is one of the newer methods of artificial ventilation used in the operating room with application of preventing aspiration, and ventilating patients suffering from broncho-plural fistula, for example. Example of a high-frequency jet ventilators that may be used is U.S. Pat. No. 4,471,773.
Presently in the operating room during surgery, HFJV can be used only when balanced anesthesia is administered. Balanced anesthesia is the use of narcotics and/or nitrous oxide with muscle relaxant drugs. Balanced anesthesia has some disadvantages in treatment of hypoxemic patients, for example, namely a high percentage of oxygen in excess of about fifty percent (50%) cannot be used.
Balanced anesthesia does not provide the broncho-dilating effect of inhalational anesthetics and awareness under anesthesia has been reported more frequently during balanced anesthesia than inhalation anesthesia.
Ordinary vaporizers normally used in anesthesia machines or ventilators can not be used because of the high pressure (20 to 50 p.s.i.) that is required during HFJV. U.S. Pat. No. 3,040,742 discloses an oxygen tent controlled inhalation therapy that contains an adjustable nozzle. An apparatus that jets respiratory gas from a ventilator is known. See U.S. Pat. No. 4,537,188.
Various patents disclose various constructions of atomizers to supply medicine to a patient. See U.S. Pat. Nos. 2,906,463 and 4,318,397. Inhalers which contain a vapor producing unit and a vapor feeding nozzle are also known. See U.S. Pat. No. 4,456,007. Apparatus for artificial respiration are also known. See U.S. Pat. No. 4,495,946. Various types of nebulizers which entrain small liquid particles in a stream of gas are known. See U.S. Pat. Nos. 3,040,742; 3,104,062; 3,172,406; 3,379,194; 3,809,080; and 4,344,574.
There remains, therefore, a very real and substantial need for a vaporizer that is compatible with high-frequency jet ventilation for use of inhalation anesthesia.